Byron took out travel insurance for a holiday to the United States. The dream trip was ruined after he was admitted to hospital with severe abdominal pain, and ended up having surgery to remove a stone.

When he made a claim, his insurer noted he'd had a similar surgery 10 years previously.

Despite having no symptoms or issues for a decade, it was treated as a pre-existing condition and Byron had to foot the entire medical bill himself.

As in previous years, pre-existing conditions are the number one cause of complaints.

Insurers have their policies sewn up tight so that if there is any "direct or indirect" connection, they can decline the claim.

Insurance Council chief executive Tim Grafton says its important to think back and disclose any pre-existing conditions when applying, otherwise you won't be covered.

"In some cases an additional premium may need to be paid to cover the extra risk of a pre-existing medical condition interrupting your travel," he says.

2. Relevant persons

It is not just your own health you have to worry about, but all your friends and family too.

Ali arranged insurance for a two-month trip to Australia. Just before she was about to leave, her mum had a stroke, and then died.

Ali cancelled all her travel arrangements, but her insurers would only foot the bill up to $5000, leaving her out of pocket for the rest.

The policy said the limit applied to an unexpected event with any relevant person if it was related to an existingmedical condition.

Ali's mum had risk factors for a stroke, and so the insurer won the Ombudsman dispute.

3. Following instructions

Insurers are very particular about when and where you get medical treatment while overseas. If you take matters into your own hands, don't be surprised if they refuse to reimburse you.

Clive and Judy arranged insurance for travel to Australia. While across the ditch, Judy got treatment for a problem with her left eye, and was told she needed surgery.

The insurer said it was not an emergency, and that Judy was fit to fly back to New Zealand to have the operation.

The couple went ahead with the surgery anyway, providing a doctor's letter which said they had an excellent retinal surgeon and there may have been time delays getting back to Auckland.

However, the insurer declined the claim, and the ISO's office upheld the decision.

The whackiest failed claim of 2014, and perhaps of all time, came from a couple of tourists visiting New Zealand for a year.

In July, Mr Lannister made a claim to get genetic testing for himself, his wife, and his daughter- because the couple had found out they were blood relations.

Having lost a baby boy in 2011, he believed it was essential for the health of his family.

The Lannisters' general practitioner said "if they are indeed carriers of a genetic disease, it would be important for us to be made aware of it at this stage".

Nevertheless, the insurer declined the claim. While most of us are unlikely to find ourselves in an icky incestuous situation, the broader lesson is that you usually can't make a claim unless there's an actual illness or injury.

5. Negligence

Many travellers enter holiday mode the moment they get poolside with a drink in their hand, and tend to forget about taking care of their stuff.

Lalit took a trip back to his hometown in India. He went for a walk to a local market for half an hour, leaving a small carry-on suitcase on the passenger seat of his friend's locked vehicle.

The suitcase contained his laptop, phone camera and clothes worth over $6000, which had disappeared when he returned.

While it might seem like a cut-and-dried claim, the insurer rejected it. It reckoned he had not taken reasonable care of his property, especially since he was aware of thefts in the area.

Instead, the insurer said he should have schlepped the 10kg suitcase with him on the walk, or crammed it in the boot- which he claimed was already full with his larger luggage.

The ISO's office looked into Lalit's complaint, and ruled his actions were indeed "grossly careless, grossly negligent, or reckless".

"The Case Manager believed [Lalit] could have made room for the suitcase in the boot of the vehicle, or at least [Lalit] could have put his laptop in the boot, and taken his phone and camera with him," it said.

6. Police report

Nicola and her husband arranged travel insurance for a backpacking adventure in South America, making sure to specify two valuable rings on the policy.

When the couple were leaving their Buenos Aires hostel, they packed the jewellery and several other items into into a toilet bag.

The couple then caught an overnight bus to Iguazu Falls, and noticed the toilet bag was gone from their backpack when they arrived.

Nicola contacted the hostel and was given the impression that staff had found it.

By the time the couple got back there, two days later, they discovered it did not have the bag after all. Nicola immediately found the nearest cop shop and filed a report before making a claim.

However, her insurer declined it, on the basis that she had not reported the loss to police within 24 hours.

The ISO reviewed the complaint, and eventually ruled in favour of the couple, given they initially thought the hostel had the bag.

The lesson is to be sure to report any thefts straight away.

7. Correct dates

Figuring out time zones when you are flitting around the world can be confusing. You don't want to accidentally call mum at three in the morning, or wish your girlfriend happy birthday the day after the event.

But it is even more crucial to make sure you have got your travel insurance booked for the correct dates. Stan bought insurance for a trip to the States from October 14 to November 11.

After an uneventful trip, he accidentally left a shoulder bag with camera equipment in a taxi outside San Francisco airport on November 12.

When the ISO's office investigated, Stan realised he had made a mistake about the time of his return flight to New Zealand.

An issue arose concerning time zones, and whether cover ended on November 11 USA time, or New Zealand time.

Eventually the insurer agreed to pay out. The lesson: Always be sure you are safely home before your cover expires.

8. Fraud

On arrival in Mumbai, Harshad discovered that a suitcase he had checked in was missing, and the airline could not find it.

He made a claim for its contents and included a document from an electronics goods store as proof of purchase.

When the insurer investigated, it found that the store's form had been altered, and it had never even stocked one of the items.

It declined his claim, a decision which the ISO supported.

Harshad's case actually cropped up in 2013, but it happens in insurance all the time. Pad out the claim with a little extra, and you will get declined for the entire thing. More importantly, you will also struggle to ever get insurance again.